After graduating he received a posting with the 1st Marik Militia as a Lieutenant. During his time in the Militia, he was assigned as aide to Captain-GeneralThomas Marik which resulted in Masters and Marik becoming life long friends.

In 3054 was brought to Atreus by Thomas Marik, where he approached him in forming a new military unit based on ideals of Chivalry. To get more understanding of what Thomas wanted, he was asked to read the ancient novel, Le Morte d'Arthur by Sir Thomas Malory. After reading the entire book in one sitting, he became enthusiastic on what Thomas was trying to do, and became one of its founding Knights.

He was among the hundred and fifty MechWarriors whom attended the ceremony of activation of Knights of the Inner Sphere on January 1st, 3055. After the ceremony, Thomas introduces Paul to Word of BlakePrecentorWilliam Blane, an old friend of the Captain-General during his ComStar days. Blane tells Thomas and Masters during the meeting that of trouble on Gibson, where his Word of Blake settlers facing rebellion against them. Thomas decides to send Masters with Blane back to Gibson to investigate the situation.

On Gibson, Masters soon discovers number of conspiracies among between Principal of Principality of Gibson & Countess Dystar, locals and Word of Blake settlers. With each of the sides fighting among themselves and individuals attempting to take control for themselves, Masters becomes a fugitive on the planet. Blane is arrested by Assistant Precentor Starling, during this time as well. Masters with assistance of some locals, manages have Duchess Dystar and her Principle ,Hsien, war among themselves with their mercenaries. Masters and other locals rescue Blane from captivity.

By February, Thomas Marik and entire Knight of the Sphere regiment arrive on planet, try resolve the situation. During this time, Masters is given the lands and title as Count of Gibson. Citing Dystar poor actions that lead to the volatile situation on the planet.
Colonel Nathen Roush of the Regulan Hussars, pledges his forces to support Dystar regain lands and join Precentor MartialTrent Arian in their fight against Masters and the Knights.

When renegade Blakist forces and Knights faces off on the battlefield of one of the capital city, where members of the Gibson Freedom League whom were denied their assistance to help in the battle for their world. They fire off their two Regulan Davey Crockett nuclear weapons against Regulans/Blakist forces on the battlefield. Reeling from the damage inflicted on them, Arian surrenders to Marik rather than fighting in the city.[2]

In 3058 Inner Sphere factions came together to reform the Star League, Captain-General Thomas Marik agrees to submit troops as part of two-prong Trial of Annihilation against one of the Clans to end the Clan threat. Masters by then had became Colonel and commanding officers of the 1st Knights of the Inner Sphere. His regiment was assigned as the FWLM contribution to Task Force Serpent, also selected by Thomas Marik to serve as the task force's conscience to keep them from becoming mindless killers.

During the year-long journey to Huntress the capital world of the Jaguars, the task force encountered pirate band which were defeated their leadership executed. This upset Masters and his people due to their beliefs of honorable conduct. A short time later, the Task Force fought a small flotilla of WarShips and a JumpShip from Clan Ghost Bear travelling to the Inner Sphere. Serpent's forces had defeated them, only to discover that the Bears' lone civilian JumpShip had been carrying thousands of civilians. Task Force commander, Morgan Hasek-Davion, ordered that the Clansmen would either swear bondmanship to the Task Force, or be marooned on a habitable world. Again Masters, and others among the Eridani Light Horse were at odds with task force decision. Masters offered take in a number of the bondsman civilians as the most civilized way to handle the situation.

In March 5th, 3060, the Task Force arrived at Huntress. Masters' 1st Knights and House Liao's Kingston's Legionnaires were directed to take Jaguars' training base at city of New Andery. There Master's Knights and his allies encountered large quantities of never before seen ProtoMechs, which inflicted considerable amounts of damage to them. During the fanatical assault cost Master's his Anvil BattleMech.

On the 19th, two make-shift Galaxies of Smoke Jaguar forces arrived from the desperate fight from their now former Occupation Zone. Masters and his Knights were assigned with the Northwind Highlanders posted southwest of Lake Osis. They became known as the Southern Army for the SLDF forces. A second force of Jaguar reinforcements arrived, lead by saKhan Brandon Howell. These forces drove the Knights and Highlanders into Dhuan Swamp, with Master's Knights being reduced to only one quarter their original strength.[3] Half of the Southern Army is routed and killed. However, during Clan attacks the Knights lead to rescue 1st Kathil Uhlans and help Southern army fight off Clan forces.

After the remains of First Prince Victor Steiner-Davion's Task Force Bulldog arrives and assists Serpent forces cleanup Huntress. After conducting a Trial of Refusal to end the invasion of the Clans, Steiner-Davion returns to Huntress and speaks with Masters. He designates him as Star League liaison to the Clans, despite Master's misgivings of the Prince's ambitions.[4][5]

↑Twilight of the Clans, p. 13 - "A Blow to Morale/Deep into the Jaguar's Fangs/On To Strana Mechty"

↑Prince of Havoc - Victor Steiner-Davion chats with Paul Masters on Huntress to become SLDF Liaison to the Clans. He tells Victor, prior to his departure to send a replacement as soon possible, not wanting to remain as permanent ambassador.